Over heating on the freeway?

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Cope

Cope

Fusing with fire
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San Jose, Ca.
71 dart, new 360
New griffen cross flow radiator. Restrictor plate in T stat housing.
Large eletric puller fan and shroud.
All new hoses.

The car is fine around town, 180-190 but get on the freeway and the temp just cimbs...

This is so backwards from all other cars I've ever owned I'm not sure what gives?

Any ideas?
 
How well is the radiator sealed to the shroud and opening??? It may be that the ram air that's supposed to be going THROUGH the radiator is going AROUND it....
 
The shroud is sealed very well.

I'm about to take it off and see what happens.
 
Lol, no
No viper involved today...
Just wanted to take my lady for a cruze.
 
Is this your race car you where talking about earlier ? New build ? And whats with the restrictor in there? No thermostat?
 
RAT ROD AL said:
Is this your race car you where talking about earlier ? New build ? And whats with the restrictor in there? No thermostat?
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A hood scoop that's not sealed to the carb. can cause that very problem, if the scoop is pulling in a lot of air and fighting the rad. airflow..
 
Cope said:
71 dart, new 360
New griffen cross flow radiator. Restrictor plate in T stat housing.
Large eletric puller fan and shroud.
All new hoses.

The car is fine around town, 180-190 but get on the freeway and the temp just cimbs...

This is so backwards from all other cars I've ever owned I'm not sure what gives?

Any ideas?
Click to expand...
Shouldn't even need a fan at freeway speeds.
The under carriage opening around the engine will let the air escape, so forget the hood scoop idea.
The fan, if on, could be blocking "not keeping up" ..the other issue is usually a capacity one...or you have too much timing and it's just pinging...or even too retarded.
 
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Ok, I dont know much, but I've read a few threads on cooling as I had an "issue" with our 67 cuda. 200 on highway and 185-190 in town. 273 4 bl, factory 3 row rad, new water pump(8 vane) last year. factory shroud. WAS running 190 stat. Timing cover coolant leak for the 2nd time in 2 years. Put a 160 stat in it and now it has not gone over 175*.
No disrespect to all the theories and such but I got a 35* temp reduction by changing tstat. $12.
Good luck.
Cope said:
71 dart, new 360
New griffen cross flow radiator. Restrictor plate in T stat housing.
Large eletric puller fan and shroud.
All new hoses.

The car is fine around town, 180-190 but get on the freeway and the temp just cimbs...

This is so backwards from all other cars I've ever owned I'm not sure what gives?

Any ideas?
Click to expand...
 
Hmmm..... the car cools fine at low speeds, but overheats on the highway. Is it possible that you have a "pusher" fan installed on the engine side of the rad, and when you drive highway speeds the fan is fighting the normal airflow? Just a wild *** guess Cope, but I've seen stuff like that accidentally happen even at the highest levels of motorsport.
Please let us know the outcome of this, it's really interesting.
 
A temperature problem at freeway speeds is almost always a radiator problem.

Seems like you’re the second person with a brand new Griffin cross flow that has cooling issues...

4spdragtop said:
Ok, I dont know much, but I've read a few threads on cooling as I had an "issue" with our 67 cuda. 200 on highway and 185-190 in town. 273 4 bl, factory 3 row rad, new water pump(8 vane) last year. factory shroud. WAS running 190 stat. Timing cover coolant leak for the 2nd time in 2 years. Put a 160 stat in it and now it has not gone over 175*.
No disrespect to all the theories and such but I got a 35* temp reduction by changing tstat. $12.
Good luck.
Click to expand...

Easy, you changed a broken thermostat for a good one. The thermostat temperature change has no part of it, besides the extra wear and tear you’re putting on your engine running it below ideal temperature.

The thermostat only sets the low temperature. If it effects anything other than the low temp, it’s not operating properly.
 
Im so Confused...My stock dart, 273 2bbl , no shroud (factory) stock fan inches from face of radiator (factory), correct thermostat, stock radiator, average water pump, no overheating issues.
 
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Dana67Dart said:
Im so Confused...My stock dart, 273 2bbl , no shroud (factory) stock fan inches from face of radiator (factory), correct thermostat, stock radiator, average water pump, no overheating issues.
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410 CID
1 " single cross row BMW radiator
18" fan
No shroud
8 blade stock water pump
Exh cross over blocked
High flow 180 t stat
16lb release rad cap
10.1 static comp
8.88 dynamic comp
Pump gas
Never overheats.
 
Garry in AZ said:
Hmmm..... the car cools fine at low speeds, but overheats on the highway. Is it possible that you have a "pusher" fan installed on the engine side of the rad, and when you drive highway speeds the fan is fighting the normal airflow? Just a wild *** guess Cope, but I've seen stuff like that accidentally happen even at the highest levels of motorsport.
Please let us know the outcome of this, it's really interesting.
Click to expand...
That's a good idea on the fan, backwards is a possibility, or it's just blocking the air at high speed once it cant keep up.
 
The fan is pulling I can feel it out the back and it would over heat in traffic it that was wrong.

I like the idea of the fan not keeping up at freeway speed. I'm running about 2500 rpm at 45 50 MPH. no speedometer, yes race car..

This is definitely an engine that's pushing the limits of streetable.
 
Old 190 thermostat wasn't broken.
72bluNblu said:
A temperature problem at freeway speeds is almost always a radiator problem.

Seems like you’re the second person with a brand new Griffin cross flow that has cooling issues...



Easy, you changed a broken thermostat for a good one. The thermostat temperature change has no part of it, besides the extra wear and tear you’re putting on your engine running it below ideal temperature.

The thermostat only sets the low temperature. If it effects anything other than the low temp, it’s not operating properly.
Click to expand...
 
20180817_170839_zpsskqltfwn.jpg


Best pic I have of the fan and shroud right now.
 
Cope said:
View attachment 1715216120

Best pic I have of the fan and shroud right now.
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Well look at that... that shroud, and now If air goes around the radiator easier than through at speed, which path do you think it would take?
Lose the shroud, its blocking more air than directing... mount the fan straight to radiator.
After that, if you still have issue...then you must seal up that core support area, seal the sides of the radiator to support.
 
Yeah so pull the shroud right?

That's a major pain in the ***. It riveted to the radiator. But I think you guys are on to something.
 
Cope said:
Best pic I have of the fan and shroud right now.
Click to expand...
IMHO your blocking 1/3 of your radiator with the shroud. Factory shrouds have space from the shroud to the radiator face and typically have a shape to promote flow.
 
Last thing I notice about the fan. It has alot of grill slats.

THink about your attic eve vents. it might cover 12"x 4" (48 sqin) but with the screen in there to keep critters out you are down to maybe 2/3 of that so maybe 32 sqin

Your fan is the same, measure the open space and you might see that you only have 1/2 the sqin of open space where air can flow through. look at the sqin of the radiator and the sqin of the opening for the fan maybe 2/3 of the rad sqin. I think all of this is the problem. loose the shroud and see what happens.
 
I do have flappers to let air out of the shroud at speed. But yeah I'm gonna try with out it.

That easy just pull radiator, drill out 35 40 rivets with out hitting the rad, build a new fan mount and test... easy peasy....

:)
 
Cope said:
The fan is pulling I can feel it out the back and it would over heat in traffic it that was wrong.

I like the idea of the fan not keeping up at freeway speed. I'm running about 2500 rpm at 45 50 MPH. no speedometer, yes race car..

This is definitely an engine that's pushing the limits of streetable.
Click to expand...

You should not even need a fan above about 35--40. On electric setups there's been talk that some electrics actually REDUCE highway airflow, you need trap doors in the shroud to bypass them

Any chance the belt is slipping?

EDIT somehow didn't see the post above, LOL. Can you take the fan OFF and run a short trip, don't know how close you are to the highway?
 
Cope said:
...no speedometer, yes race car... pushing the limits of streetable.
Click to expand...

Cope said:
That's a major pain in the ***. It riveted to the radiator. But I think you guys are on to something.
Click to expand...

Cope said:
That easy just pull radiator, drill out 35 40 rivets with out hitting the rad, build a new fan mount and test... easy peasy....:)
Click to expand...

man, nothing with "race car" and "pushing the limits of streetable" should be that difficult to disassemble :rolleyes:
 
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